Re: LCD Based Printer; Photopolymer Samples
- Hi Ali,
Im in Kelowna, BC.
The printer is still in its early prototype stage, but it is working. Still much work to do to get it out as a DIY kit.
As for answers,
The color LCD's color filters loose to much light and the red and green block all light leaving holes in the print.
Im using a glass vat, you cannot use the LCD as a vat bottom because any pressure disturbs the liquid crystal. Light does diffuse, but I have it down to a resonable level using optics and having the light collimated. Cure times are around 8-10seconds, but hope to be less with Fernandos new resins.
Bulb was only $45, its double ended and a 400w MH, you can use ones for Coral reefs in the 10000k+ range.
Greyscale LCD's I get from a chinese supplier, they are pricey, $800/LCD with controller. Used ones can be found for $100-200 on ebay, but there is no telling if it will work or not. Most medical LCD require a special video card.
Once I get some time i'll write up all my finding and help others build and perfect the LCD 3d Printer, It does have some great promise!
--- In email@example.com, Ali Punjani <ali.punjani.groups@...> wrote:
> Hi Nick!
> Thanks for replying to my post, I was hoping you might.
> It's great to hear from a fellow Canadian! I'm in Toronto (East), how about
> I think it's awesome that you're planning to release a DIY kit for this
> sort of project. Also self replication is a good idea. If you're working on
> software, does that mean the mechanical/optical/chemical parts of the
> printer are working well now?
> If you have a minute, I have a few questions for you:
> What exactly was wrong with a color LCD, were the blue color filters and
> red/green pixels just blocking too much of the useful light?
> How did you manage to solve the issue of diffusion of light leaving the LCD
> Panel? Was it enough to simply use the LCD panel itself as the vat bottom?
> Does the light from the MH lamp need to be collimated?
> What kinds of cure times do you get?
> I read a lot about metal-halide and mercury vapour bulbs over the last few
> days, and I had looked into some MH lamps made for aquariums - They seem to
> have the types of spectral output you mentioned. A custom lamp must have
> been pretty expensive! Similarly with the Monochrome LCD panels - the only
> place I can find them is on eBay, and they are very expensive - $700 to
> $1000. I was hoping to get going with a plain color LCD which can be gutted
> from a photoframe for ~$50. I assume you've found a way to get monochrome
> LCDs for cheap, if you plan a DIY kit?
> I'm certainly looking forward to when you have a chance to write about
> everything you've learned through the testing process. I think I'll start
> experimenting too, I just finished building a CNC router and I'm looking
> for a new project to use it for :p
> On Thu, Feb 21, 2013 at 10:53 PM, phife54@... <phife54@...>wrote:
> > **
> > Hi Ali,
> > A fellow Canadian, where abouts are you?
> > I have been developing an LCD based 3d printer for the last 6 months,
> > While my thread has been quiet for some time, rest assured ive been
> > plugging away at it.. Its not been a simple matter. Ive done a lot of
> > testing with different resins, LCD's, Light sources, Lenses, and
> > Electronics.
> > I am hoping to release a DIY kit for others to build their own LCD 3D
> > printer. Im working with Chris Marion and we are developing a great
> > machine, I will be using a custom version of Chris's software.
> > Dont waste your time with color LCD, you will need a monochrome LCD no
> > matter what.
> > My current setup is using a custom 400w MH bulb on a digital ballast, this
> > bulb has a small arc and a very high output in the 390-420nm range and has
> > a large spike at 450nm and not much of the spectrum after that, its a very
> > nice purple/blue color. Optics are very important, and dealing with the
> > heat of the 400w MH bulb must also be address.
> > I havent had much success with any other bulbs, I was testing with a 150w
> > MH and a regular 400w MH but they didnt work out.
> > The nice thing about the LCD printer is the large build area, I hope to be
> > able to print the entire structure of the printer with the prototype in a
> > reprap style. Print panels, add hardware and electronics and you got a
> > printer. Ive been designing printable panels but there is much to deal with
> > before I even begin printing other machines.
> > You will have to deal with all the issues youve listed and more, and its a
> > big task. I encourage you to experiment and try. To start off save you
> > money and dont bother with color LCD's get a monochrome or greyscale LCD
> > used for medical purposes, x-ray imaging.
> > If you wait a couple more months I hope to have a working printer and I
> > can spend some time getting a DIY kit out there and write up all that ive
> > learned from my testing ao rhat others can make their own.
> > I wish you luck!
> > Nick